The corpus luteum synthesizes and secretes the steroid hormone progesterone which is required for the establishment and maintenance of pregnancy. The corpus luteum and the secretion of progesterone also regulates the duration of menstrual cycles in women and estrous cycles in domestic animals. Manipulation of the corpus luteum has resulted in contraceptives for women and means of synchronizing estrous cycles in domestic animals. Yet the high rate of embryonic mortality (approximately 50% in women, 16-42% in livestock) and undesirable side effects of current contraceptives for some women dictates new methods to govern the corpus luteum be investigated. Polyamines regulate cell growth and intracellular functions. However, the role of polyamines and corpus luteum function has not been studied. The research proposed will examine the role of polyamines and the synthesis of progesterone and expression of mRNA encoding the steroidogenic enzymes within the corpus luteum. Cell culture and molecular biology techniques will be used to accomplish these objectives utilizing ewes, which are used by numerous researchers as animal models for both humans and other domestic animals. Corpora lutea will be obtained from ewes on day 10 of the estrous cycle. Luteal tissue will be enzymatically digested to yield single cell suspensions. Cultured cells will be treated with polyamines and progesterone secretion will be measured by RIA. Cultured cells will be harvested and mRNA extracted. mRNA encoding the steroidogenic enzymes will be analyzed by Northern blot hybridization methods. Students will receive comprehensive training in cell/tissue culture and molecular biology techniques required to be competitive in numerous scientific fields.